The present invention concerns a holder for retaining a sheet-like, X-ray sensitive medium of the type used in making X-ray pictures.
Such holders are employed for making X-ray exposures on conventional X-ray film or a stimulable phosphor imaging plate. The film is often secured in a holder in the form of a cassette while being exposed. Once the picture has been taken, the sheet-like medium is removed from the cassette for processing. The conventional films are developed conventionally and the phosphor imaging plates are excited, point by point, by a beam of light, usually a laser. The phosphorescence is scanned electro-optically, generating electronic image signals that can be further processed digitally in a computer.
The cassettes are automatically loaded with either type of X-ray sensitive medium by inserting them in a cassette loader. The cassette is loaded inside the loader, which is light-proof, with a fresh film of whatever type is desired. The loaded cassette is then inserted into the X-ray apparatus ready for exposure.
X-rays are employed in many fields, in non-destructive materials testing for example and especially for medical diagnoses. Medical X-ray pictures must be produced rapidly, especially in emergencies. Mobile X-ray apparatus is usually employed for bedridden or wounded patients. Such apparatus is positioned over the patient being radiographed and the loaded cassette is positioned beneath the patient. A bedridden patient accordingly has to be lifted in order to slide the cassette in under him or her. The cassette must then be positioned correctly in relation to the regions being imaged. Experience demonstrates that conventional cassettes are difficult to slide in under a patient and, once there, to position correctly for exposure. The cassette is of course also difficult to remove once the exposure has been made. Cassettes are sometimes severely stressed mechanically by heavy patients, and can even break as a result.